Google seems to be working on a note-taking app akin to Evernote and, indeed, its old and retired Google Notebook service.
The app is dubbed
Keep and it's part of Google Drive. Some hints of the app were spotted last summer, but it's now been temporarily
enabled, perhaps in error or as a test, for some users.
Google quickly disabled it again, but not before it was spotted. The app works pretty much like you expect, you can create several types of notes, for example lists or just simple text notes.
All your existing notes will be listed in a thumbnail-style gallery, though you can switch to a list view. The web app works on mobile devices, though a mobile
app is in the works as well, it seems.
The impression from those that managed to use the app before it was removed, was that Keep is still rough around the edges. That's even though there were hints of a Keep up as early as last summer.
This may be an indication that Keep is more complex than it seems and still being developed, or that Google abandoned it and didn't bother to remove the code just yet. It's probably the former.